Production Scheduling For Machining Workshops Incorporating Bottleneck Adaptive Regulation

Due to the diversification and customization of market demands,more and more machining workshops adopt mass customization production mode.Since the varieties of the products are switched more frequently and the load of the machine is increasing,the machine is often blocked or shut down due to lack of material,which has adverse effects on the production stability and efficiency.For such a production situation,it is necessary to evaluate the changes of bottleneck correspondingly in real-time,and design a scheduling strategy with adaptive bottleneck adjustment ability.This method can effectively guide the migration of bottleneck,and balance the workloads among resources,and smooth production operation,so as to gain comprehensive performance is more optimal scheduling scheme.Hence,to achieve the goal of an efficient,stable and balanced production,this paper studies the machining shop scheduling with adaptive bottleneck adjustment from the aspects of adaptive bottleneck regulation framework,scheduling and rescheduling models and algorithms based on the above framework.Specific research contents are included as follows.Firstly,this paper proposes a load-balance-oriented adaptive bottleneck regulation framework.This framework establishes a bottleneck degree evaluation system based on the advantage/disadvantage solution distance method by using the machine utilization rate,load and average active time,to effectively evaluate the bottleneck degree of each machine.This framework embeds the bottleneck degree into the production schedule to control the whole production and and the load rate of each machine is optimized at the same time of the production control,so as to realize the adaptive control of the bottleneck.This framework modifies the scheduling scheme according to the bottleneck degree to ensure that the current scheduling scheme matches the degree of the bottleneck.The final results based on test instances indicate that the proposed framework can improve load-balance and reduce the negative effects of bottlenecks,and accordingly improve the production efficiency.Secondly,for machining workshop scheduling with fixed bottlenecks,this paper studies the basic methods of synchronous optimization of production efficiency and workload.This paper first analyzes the relationship between fixed bottleneck and operation tasks,in order to present an approach to reduce the load of bottleneck.Next,with fixed bottleneck utilization as the constraint,a production scheduling model is constructed to minimize manufacturing cycle and maximum machine load.Then,an improved artificial bee colony optimization algorithm is also designed to solve this problem in this paper.Mass experimental results prove the effectiveness of the proposed model and algorithm.Then,for the machining workshop production scheduling problem with bottleneck drift in multi-variety production,this paper further studies the synchronous optimization method of production efficiency and workload under the adaptive bottleneck regulation framework.The bottleneck degree of each machine is integrated into the production scheduling model in the form of constraint conditions and objective functions to limit the maximum load of the machine and improve the load balance goal.Then,through the cooperative optimization of machine load assignment and job sequence,a shop scheduling model with adaptive bottleneck regulation is developed.Meanwhile,an improved migrating birds optimization algorithm is designed to tackle this problem.The algorithm includes a problem-specificoriented initialization,neighborhood structure and competition mechanism to strengthen its local and global stability.Experimental results show that the proposed method can effectively reduce the impact of bottleneck drift,and the proposed model and solution method are effective.Furthermore,aiming at the machining workshop production rescheduling problem with an rush order and bottleneck drift,this paper studies the optimization method of production efficiency and workload responding to order changes under the adaptive bottleneck regulation framework.For the rush order insertion,this paper analyzes the complete rearrangement and partial rearrangement strategies,and their application scope.And then a mixed-integer programming model is constructed.Meanwhile,this paper designs a new improved migrating birds optimization algorithm based on the problem characteristics.Specifically,a heuristic-based initialization and strengthening joint neighborhood structure is designed to improve the initial solution performance and local exploration ability.The queue information-based regrouping competition mechanism is proposed to further improve global ability.Through the above improvements,this algorithm can achieve the balance between exploration and utilization abilities.The experimental results show that this method can improve the production efficiency and ensure the load balance of the machine despite of the bottleneck drift and rush orders.Finally,this paper studies the actual production of a valve parts machining workshop.After analyzing the production characteristics,this problem is summarized as a flexible job shop scheduling with fixed bottleneck and bottleneck drift.The current paper solves such a problem by the proposed artificial bee colony optimization and improved migrating birds optimization algorithm with considering the real production data.End results verify the feasibility and effectiveness of the proposed framework and method well.